Editing Cold air intakes

Making a CAI, or a shortram intake

pic on a Saturn engine http://hotrodders.com/gallery/showphoto.php/photo/18082/cat/3121/page/1

This is really quite simple.

First you need to know the diameter of the stock intake tubing, and where you want your filter- usually a cone type reusable gauze type from S&B or K&N work well for these applications.

Second, you need to be sure to provide fittings for vaccum and pcv lines, or if it won't upset sensors capping them off or putting a breather on works as well (with my Saturn shown in the pic, I capped off the pcv provision and put a KN breather on).  Also ensure provisions for sensors, although intake air temp sensors may be placed relatively near the air filter, or a cooler location for a slightly richer mixuture if that's desired.  I would not risk upsetting sensor readings by cutting and splicing the wires on it though.

Third you need the right assortment of elbows, tubing, clamps, and possibly some length of pcv hose if the stock stuff cannot reach the nipples on the pipe that the pcv lines are to connect to.  Sometimes grabbing a dirt cheap intake kit is useful for the smooth piping to replace the bumpy crappy factory stuff.  

So now you have measured everything- length, diameter, etcetera.  You have your supplies, and now you test fit everything without clamps and adjust as necessary to get everything to fit as you want; once that is achieved, install clamps and filter, connect pcv lines and sensors, and there you go!

The main difference between a cold air intake and a shortram is that a shortram is simpler, and the filter is in the engine compartment, drawing in warmer air.  A cold air intake is more complicated and the filter is usually in the fender or otherwise isolated from engine compartment heat.